diff --git a/src/flow/binary.rs b/src/flow/binary.rs
index a7aa556..e4dd68e 100644
--- a/src/flow/binary.rs
+++ b/src/flow/binary.rs
@@ -8,32 +8,34 @@ use std::fmt::Display;
 use crate::flow::comparator::*;
 use crate::func::{context::*, *};
 
-pub type Split<'a, BT> = (
-    <BT as BinaryTrees<'a>>::Tree,
-    <BT as BinaryTrees<'a>>::Tree,
-    <BT as BinaryTrees<'a>>::Key,
+pub type Split<BT> = (
+    <BT as BinaryTrees>::Tree,
+    <BT as BinaryTrees>::Tree,
+    <BT as BinaryTrees>::Key,
 );
-pub type KeySplit<'a, BT> = (<BT as BinaryTrees<'a>>::Tree, <BT as BinaryTrees<'a>>::Tree);
+pub type KeySplit<BT> = (<BT as BinaryTrees>::Tree, <BT as BinaryTrees>::Tree);
 
 pub type BTWrap<'a, BT, A> = WrapC<'a, A, BT>;
 
-pub trait BinaryTrees<'a>: FunctorContext<'a, T = Self::_Tm> + Clone {
+pub trait BinaryTrees: Clone {
     type Node: Send;
     type Reference: Send;
     type Tree: Send;
     type Key: Send + Clone;
     type Comparator: Comparator<Self::Key>;
+}
 
+pub trait MonadTrees<'a>: FunctorContext<'a, T = Self::_Tm> + BinaryTrees {
     type _Tm: Monad<'a>;
 
     fn comparator(&self) -> &Self::Comparator;
-    fn split(&self, node: &Self::Node) -> Split<'a, Self>;
+    fn split(&self, node: &Self::Node) -> Split<Self>;
     fn resolve(&self, reference: &Self::Reference) -> BTWrap<'a, Self, Self::Node>;
     fn equal(&self, rl: &Self::Reference, rr: &Self::Reference) -> bool;
     fn refer(&self, tree: &Self::Tree) -> Option<Self::Reference>;
 }
 
-pub trait BinaryTreesTreeOf<'a>: BinaryTrees<'a> {
+pub trait BinaryTreesTreeOf<'a>: MonadTrees<'a> {
     fn tree_of(&self, node: Self::Node) -> BTWrap<'a, Self, Self::Tree>;
 
     fn tree_bind(self, fnode: BTWrap<'a, Self, Self::Node>) -> BTWrap<'a, Self, Self::Tree> {
@@ -41,14 +43,11 @@ pub trait BinaryTreesTreeOf<'a>: BinaryTrees<'a> {
     }
 }
 
-pub trait BinaryTreesEmpty<'a>: BinaryTrees<'a> {
+pub trait BinaryTreesEmpty<'a>: MonadTrees<'a> {
     fn empty(&self) -> Self::Tree;
 
-    fn split_key_empty(
-        &self,
-        tree: Self::Tree,
-        key: Self::Key,
-    ) -> BTWrap<'a, Self, KeySplit<'a, Self>>;
+    fn split_key_empty(&self, tree: Self::Tree, key: Self::Key)
+        -> BTWrap<'a, Self, KeySplit<Self>>;
 }
 
 pub trait BinaryTreesMutable<'a>: BinaryTreesEmpty<'a> + BinaryTreesTreeOf<'a> {
@@ -91,11 +90,7 @@ pub trait BinaryTreesMutable<'a>: BinaryTreesEmpty<'a> + BinaryTreesTreeOf<'a> {
         })
     }
 
-    fn split_key_node(
-        self,
-        node: Self::Node,
-        key: Self::Key,
-    ) -> BTWrap<'a, Self, KeySplit<'a, Self>> {
+    fn split_key_node(self, node: Self::Node, key: Self::Key) -> BTWrap<'a, Self, KeySplit<Self>> {
         let (tl, tr, k) = self.split(&node);
         match self.comparator().compare(&key, &k) {
             Comparison::L => Self::bind(self.clone().split_key(tl, key), move |(tll, tlr)| {
@@ -108,7 +103,7 @@ pub trait BinaryTreesMutable<'a>: BinaryTreesEmpty<'a> + BinaryTreesTreeOf<'a> {
         }
     }
 
-    fn split_key(self, tree: Self::Tree, key: Self::Key) -> BTWrap<'a, Self, KeySplit<'a, Self>> {
+    fn split_key(self, tree: Self::Tree, key: Self::Key) -> BTWrap<'a, Self, KeySplit<Self>> {
         match self.refer(&tree) {
             Some(reference) => Self::bind(self.resolve(&reference), |node| {
                 self.split_key_node(node, key)
@@ -151,12 +146,12 @@ impl Display for HeightError {
     }
 }
 
-pub trait BinaryTreesHeight<'a>: BinaryTrees<'a> {
+pub trait BinaryTreesHeight<'a>: MonadTrees<'a> {
     fn height(&self, tree: &Self::Tree) -> u64;
     fn height_error<T: 'a + Send>(&self, error: HeightError) -> BTWrap<'a, Self, T>;
 }
 
-pub trait BinaryTreesTryJoin<'a>: BinaryTrees<'a> {
+pub trait BinaryTreesTryJoin<'a>: MonadTrees<'a> {
     fn try_join(
         &self,
         tl: Self::Tree,
diff --git a/src/flow/binary/avl.rs b/src/flow/binary/avl.rs
index 5f3bbd5..97b8871 100644
--- a/src/flow/binary/avl.rs
+++ b/src/flow/binary/avl.rs
@@ -1,12 +1,12 @@
 use super::*;
 
-trait IntoTree<'a, Trees: BinaryTrees<'a>> {
+trait IntoTree<'a, Trees: MonadTrees<'a>> {
     fn into_tree(self, trees: &Trees) -> BTWrap<'a, Trees, Trees::Tree>;
 }
 
 struct T<T>(T);
 
-impl<'a, Trees: BinaryTrees<'a>> IntoTree<'a, Trees> for T<Trees::Tree> {
+impl<'a, Trees: MonadTrees<'a>> IntoTree<'a, Trees> for T<Trees::Tree> {
     fn into_tree(self, _trees: &Trees) -> BTWrap<'a, Trees, Trees::Tree> {
         Trees::pure(self.0)
     }
diff --git a/src/flow/binary/balancing.rs b/src/flow/binary/balancing.rs
index c48c637..c36fed7 100644
--- a/src/flow/binary/balancing.rs
+++ b/src/flow/binary/balancing.rs
@@ -84,24 +84,22 @@ fn matches_height(hl: u64, hr: u64, hp: u64) -> Result<(), BalancingError> {
     }
 }
 
-impl<'a, BT: BinaryTreesUnbalanced<'a>> BinaryTrees<'a> for BalancedTrees<BT> {
+impl<BT: BinaryTrees> BinaryTrees for BalancedTrees<BT> {
     type Node = BT::Node;
-
     type Reference = (BT::Reference, u64);
-
     type Tree = BT::Tree;
-
     type Key = BT::Key;
-
     type Comparator = BT::Comparator;
+}
 
+impl<'a, BT: BinaryTreesUnbalanced<'a>> MonadTrees<'a> for BalancedTrees<BT> {
     type _Tm = Self::T;
 
     fn comparator(&self) -> &Self::Comparator {
         self.0.comparator()
     }
 
-    fn split(&self, node: &Self::Node) -> Split<'a, Self> {
+    fn split(&self, node: &Self::Node) -> Split<Self> {
         self.0.split(node)
     }
 
@@ -143,7 +141,7 @@ impl<'a, BT: BinaryTreesUnbalanced<'a> + BinaryTreesEmpty<'a>> BinaryTreesEmpty<
         &self,
         tree: Self::Tree,
         key: Self::Key,
-    ) -> BTWrap<'a, Self, KeySplit<'a, Self>> {
+    ) -> BTWrap<'a, Self, KeySplit<Self>> {
         self.0.split_key_empty(tree, key)
     }
 }
diff --git a/src/flow/binary/bound.rs b/src/flow/binary/bound.rs
index 829b691..feb3696 100644
--- a/src/flow/binary/bound.rs
+++ b/src/flow/binary/bound.rs
@@ -43,7 +43,7 @@ impl<'a, BT: FunctorContext<'a>> FunctorContext<'a> for BoundTrees<BT> {
     type T = BT::T;
 }
 
-pub trait BinaryTreesBindable<'a>: BinaryTrees<'a> {
+pub trait BinaryTreesBindable<'a>: MonadTrees<'a> {
     fn bounds_error<T: 'a + Send>(&self, error: BoundsError<Self::Key>) -> BTWrap<'a, Self, T>;
 
     fn bounds_bind<A: 'a + Send, B: 'a + Send>(
@@ -58,24 +58,22 @@ pub trait BinaryTreesBindable<'a>: BinaryTrees<'a> {
     }
 }
 
-impl<'a, BT: BinaryTreesBindable<'a>> BinaryTrees<'a> for BoundTrees<BT> {
+impl<BT: BinaryTrees> BinaryTrees for BoundTrees<BT> {
     type Node = BoundNode<Self::Key, BT::Node>;
-
     type Reference = Bound<Self::Key, BT::Reference>;
-
     type Tree = Bound<Self::Key, BT::Tree>;
-
     type Key = BT::Key;
-
     type Comparator = BT::Comparator;
+}
 
+impl<'a, BT: BinaryTreesBindable<'a>> MonadTrees<'a> for BoundTrees<BT> {
     type _Tm = Self::T;
 
     fn comparator(&self) -> &Self::Comparator {
         self.0.comparator()
     }
 
-    fn split(&self, node: &Self::Node) -> Split<'a, Self> {
+    fn split(&self, node: &Self::Node) -> Split<Self> {
         let (tl, tr, key) = self.0.split(&node.node);
         (
             Bound {
@@ -147,7 +145,7 @@ impl<'a, BT: BinaryTreesBindable<'a> + BinaryTreesEmpty<'a>> BinaryTreesEmpty<'a
         &self,
         tree: Self::Tree,
         key: Self::Key,
-    ) -> BTWrap<'a, Self, KeySplit<'a, Self>> {
+    ) -> BTWrap<'a, Self, KeySplit<Self>> {
         self.0.bounds_bind(
             tree.bounds.split(&key, self.comparator()),
             |(boundsl, boundsr)| {
diff --git a/src/mrds/trees/heighted.rs b/src/mrds/trees/heighted.rs
index 2fa4d4b..a22d126 100644
--- a/src/mrds/trees/heighted.rs
+++ b/src/mrds/trees/heighted.rs
@@ -86,24 +86,22 @@ impl<'a, A: 'a + Send> FunctorContext<'a> for Trees<A> {
     type T = instances::solo::SoloInstance;
 }
 
-impl<'a, A: 'a + Send + Sync + Ord + Clone> BinaryTrees<'a> for Trees<A> {
+impl<A: Send + Sync + Ord + Clone> BinaryTrees for Trees<A> {
     type Node = Node<A>;
-
     type Reference = Reference<A>;
-
     type Tree = Tree<A>;
-
     type Key = A;
-
     type Comparator = DefaultComparator;
+}
 
+impl<'a, A: 'a + Send + Sync + Ord + Clone> MonadTrees<'a> for Trees<A> {
     type _Tm = Self::T;
 
     fn comparator(&self) -> &Self::Comparator {
         &DefaultComparator
     }
 
-    fn split(&self, node: &Self::Node) -> Split<'a, Self> {
+    fn split(&self, node: &Self::Node) -> Split<Self> {
         (node.l.clone(), node.r.clone(), node.key.clone())
     }
 
@@ -142,7 +140,7 @@ impl<'a, A: 'a + Send + Sync + Ord + Clone> BinaryTreesEmpty<'a> for Trees<A> {
         &self,
         _tree: Self::Tree,
         _key: Self::Key,
-    ) -> BTWrap<'a, Self, KeySplit<'a, Self>> {
+    ) -> BTWrap<'a, Self, KeySplit<Self>> {
         (self.empty(), self.empty())
     }
 }
diff --git a/src/rstd/collections/tree/context.rs b/src/rstd/collections/tree/context.rs
index 1fcc448..ebd330a 100644
--- a/src/rstd/collections/tree/context.rs
+++ b/src/rstd/collections/tree/context.rs
@@ -56,7 +56,8 @@ impl<'a, Ctx: Context<'a>, A: Mentionable<'a, Ctx>, E: 'a> From<HeightError>
     }
 }
 
-pub type TreeContext2<'a, Ctx, A, C, E> = TreeContext<(Arc<C>, Fctr<'a, Ctx, A>), (Ctx, A, E)>;
+pub type TreeContext2<'a, Ctx, A, C, E> =
+    TreeContext<(Arc<C>, Fctr<'a, Ctx, A>), (&'a (), Ctx, A, E)>;
 
 impl<
         'a,
@@ -75,25 +76,30 @@ impl<
         A: Mentionable<'a, Ctx> + Clone,
         C: 'a + Comparator<A>,
         E: 'a + Send,
-    > BinaryTrees<'a> for TreeContext2<'a, Ctx, A, C, E>
+    > BinaryTrees for TreeContext2<'a, Ctx, A, C, E>
 {
     type Node = Node<'a, Ctx, A>;
-
     type Reference = Point<'a, Ctx, Self::Node>;
-
     type Tree = Tree<'a, Ctx, A>;
-
     type Key = A;
-
     type Comparator = C;
+}
 
+impl<
+        'a,
+        Ctx: Context<'a>,
+        A: Mentionable<'a, Ctx> + Clone,
+        C: 'a + Comparator<A>,
+        E: 'a + Send,
+    > MonadTrees<'a> for TreeContext2<'a, Ctx, A, C, E>
+{
     type _Tm = Self::T;
 
     fn comparator(&self) -> &Self::Comparator {
         self.0 .0.as_ref()
     }
 
-    fn split(&self, node: &Self::Node) -> crate::flow::binary::Split<'a, Self> {
+    fn split(&self, node: &Self::Node) -> crate::flow::binary::Split<Self> {
         (node.l.clone(), node.r.clone(), node.key.clone())
     }
 
@@ -136,7 +142,7 @@ impl<
         &self,
         _tree: Self::Tree,
         _key: Self::Key,
-    ) -> BTWrap<'a, Self, KeySplit<'a, Self>> {
+    ) -> BTWrap<'a, Self, KeySplit<Self>> {
         Self::pure((self.empty(), self.empty()))
     }
 }